10,754 research outputs found
Thermodynamics of Higher Spin Black Holes in AdS
We discuss the thermodynamics of recently constructed three-dimensional
higher spin black holes in SL(N,R)\times SL(N,R) Chern-Simons theory with
generalized asymptotically-anti-de Sitter boundary conditions. From a
holographic perspective, these bulk theories are dual to two-dimensional CFTs
with W_N symmetry algebras, and the black hole solutions are dual to thermal
states with higher spin chemical potentials and charges turned on. Because the
notion of horizon area is not gauge-invariant in the higher spin theory, the
traditional approaches to the computation of black hole entropy must be
reconsidered. One possibility, explored in the recent literature, involves
demanding the existence of a partition function in the CFT, and consistency
with the first law of thermodynamics. This approach is not free from
ambiguities, however, and in particular different definitions of energy result
in different expressions for the entropy. In the present work we show that
there are natural definitions of the thermodynamically conjugate variables that
follow from careful examination of the variational principle, and moreover
agree with those obtained via canonical methods. Building on this intuition, we
derive general expressions for the higher spin black hole entropy and free
energy which are written entirely in terms of the Chern-Simons connections, and
are valid for both static and rotating solutions. We compare our results to
other proposals in the literature, and provide a new and efficient way to
determine the generalization of the Cardy formula to a situation with higher
spin charges.Comment: 30 pages, PDFLaTeX; v2: typos corrected, explicit expressions for the
free energy adde
Surface dissipation in nanoelectromechanical systems: Unified description with the standard tunneling model and effects of metallic electrodes
By modifying and extending recent ideas [C. Seoanez et al., Europhys. Lett.
78, 60002 (2007)], a theoretical framework to describe dissipation processes in
the surfaces of vibrating micro- and nanoelectromechanical devices, thought to
be the main source of friction at low temperatures, is presented. Quality
factors as well as frequency shifts of flexural and torsional modes in doubly
clamped beams and cantilevers are given, showing the scaling with dimensions,
temperature, and other relevant parameters of these systems. Full agreement
with experimental observations is not obtained, leading to a discussion of
limitations and possible modifications of the scheme to reach a quantitative
fitting to experiments. For nanoelectromechanical systems covered with metallic
electrodes, the friction due to electrostatic interaction between the flowing
electrons and static charges in the device and substrate is also studied.Comment: 17 pages, 7 figure
Use of archival versus newly collected tumor samples for assessing PD-L1 expression and overall survival : an updated analysis of KEYNOTE-010 trial
Background: In KEYNOTE-010, pembrolizumab versus docetaxel improved overall survival (OS) in patients with programmed death-1 protein (PD)-L1-positive advanced non-small-cell lung cancer (NSCLC). A prespecified exploratory analysis compared outcomes in patients based on PD-L1 expression in archival versus newly collected tumor samples using recently updated survival data.
Patients and methods: PD-L1 was assessed centrally by immunohistochemistry (22C3 antibody) in archival or newly collected tumor samples. Patients received pembrolizumab 2 or 10 mg/kg Q3W or docetaxel 75 mg/m2 Q3W for 24 months or until progression/intolerable toxicity/other reason. Response was assessed by RECIST v1.1 every 9 weeks, survival every 2 months. Primary end points were OS and progression-free survival (PFS) in tumor proportion score (TPS) 50% and 1%; pembrolizumab doses were pooled in this analysis.
Results: At date cut-off of 24 March 2017, median follow-up was 31 months (range 23-41) representing 18 additional months of follow-up from the primary analysis. Pembrolizumab versus docetaxel continued to improve OS in patients with previously treated, PD-L1-expressing advanced NSCLC; hazard ratio (HR) was 0.66 [95% confidence interval (CI): 0.57, 0.77]. Of 1033 patients analyzed, 455(44%) were enrolled based on archival samples and 578 (56%) on newly collected tumor samples. Approximately 40% of archival samples and 45% of newly collected tumor samples were PD-L1 TPS 50%. For TPS 50%, the OS HRs were 0.64 (95% CI: 0.45, 0.91) and 0.40 (95% CI: 0.28, 0.56) for archival and newly collected samples, respectively. In patients with TPS 1%, OS HRs were 0.74 (95% CI: 0.59, 0.93) and 0.59 (95% CI: 0.48, 0.73) for archival and newly collected samples, respectively. In TPS 50%, PFS HRs were similar across archival [0.63 (95% CI: 0.45, 0.89)] and newly collected samples [0.53 (95% CI: 0.38, 0.72)]. In patients with TPS 1%, PFS HRs were similar across archival [0.82 (95% CI: 0.66, 1.02)] and newly collected samples [0.83 (95% CI: 0.68, 1.02)].
Conclusion: Pembrolizumab continued to improve OS over docetaxel in intention to treat population and in subsets of patients with newly collected and archival samples
Interviewing Peter Gow — Dundee, June 24, 2017
This interview presents an initial dialogue about Peter Gow’s trajectory as an anthropologist, trying to bring to light particularly the fieldwork experiences and events that it had not been possible to commenton and explore in the published material. Its aim is to understand more closely the particular ways in which Peter Gow had come to arrive at the insights and the analyses presented in his brilliant ethnographies with the Yine/Piro people of Amazonia
Dry Matter Yield and Nutritive Value of Coast-Cross N1 Preserved as Hay, Silage, and Haylage
Dry matter yield and nutritive value of coast-cross n° 1 (Cynodon dactylon (L.) Pers preserved as hay, silage and haylage were studied. The forage was harvested after 28, 35, 42 and 49 days of growth. Fertilization was completed with 400 kg/ha single superphosphate and 500 kg/ha 20-0-20 at the beginning of the experiment. The experimental design for dry matter yield (2 x 2 m plots) was a randomized block with four replications. Nutritive value was also analyzed in a randomized block design being the treatments arranged in a 3 x 4 factorial (three preservation methods and four ages). Dry matter yield increased linearly (P \u3c 0,05) with age, whilst crude protein content had an opposite effect. Dry matter content was not affected by age (P \u3e 0.05). Nutritive value of haylage was greater than those observed for hay and silage
Pathway to an excitonic coherence
This paper discusses the combined effects of optical excitation power,
interface roughness, lattice temperature, and applied magnetic fields on the
spin-coherence of excitonic states in GaAs/AlGaAs multiple quantum wells. For
low optical powers, at lattice temperatures between 4 K and 50 K, the
scattering with acoustic phonons and short-range interactions appear as the
main decoherence mechanisms. Statistical fluctuations of the band-gap however
become also relevant in this regime and we were able to deconvolute them from
the decoherence contributions. The circularly polarized
magneto-photoluminescence unveils a non-monotonic tuning of the coherence for
one of the spin components at low magnetic fields. This effect has been
ascribed to the competition between short-range interactions and spin-flip
scattering, modulated by the momentum relaxation time
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